Blown 440 head gaskets

[Morris'_Mopars]

I have been blowin head gasket alot lately. They are blowing out the front by the dowl pin. Is this due to crank case psi?? I notice when I turn off my engine I can hear a psi release like noise for a second. I thought it was my previous block but I blew another gasket last week. Also had the heads checked and they are fine. Any help or    is appreciated.
 

[Chryco Psycho]

crank case pressure should never put pressure on the head gasket
 are you using an iron block / alum head combo ?
 if so I only recommend using Cometic head gaskets

[tactransman]

You haven't had any milling done (deck or head surface) where the dowel pin is too long now keeping the gasket from getting clamped good in that spot have you?

[moper]

Like they asked..what is the whole combo? With 17 headbolts, BB mopars should never blow head gaskets..lol.

[Morris'_Mopars]

Cast iron 516 closed chamber heads and cast iron block and fel pro gasket. I dont have the heads plained all pretty much standard.

[Morris'_Mopars]

You haven't had any milling done (deck or head surface) where the dowel pin is too long now keeping the gasket from getting clamped good in that spot have you?

I have even changed blocks, thinking the block was bad.

[moper]

Are you using factory bolts? Are there any marks on the dowels say from vice grips or anything? with the thicker head gaskets (factory is stamped steel like the MPs) the dowels shouldnt be anywhere near bottoming out in the head. Have you tapped out every head bolt hole with a bottoming tap? (not one that's tapered..the bottoming ones are almost flat like an end mill) Do you use a torque wrech, and tighten in the proper steps and sequence? You should be going in 3 steps. IIRC, the final spec is 85 pound feet. So, tap the holes and blow them out with compressed air. Wire wheel the bolts themselves to get any crud out of the threads. Use 30W oil (not 10-40, 10-30 would be ok) on the threads, and only a little, dont get it all over the place. No finger prints or grease allowed on the head or block gasket surfaces. Clean it with a clean paper towel or lint free rag, then dont touch either surface with your hands. Put the head in place, start with the center bolts (I start all the bolts by hand as far as I can go) and torque them all to 40 pound feet. Then go back, torque them all to 65. Then finally go back and get them all to 85 in a smooth motion. I've done over 50 engiens this way, and never had a leak or blown gasket due to "normal" use. (NOS will kill the small block ones tho..

[Morris'_Mopars]

Are you using factory bolts? Are there any marks on the dowels say from vice grips or anything? with the thicker head gaskets (factory is stamped steel like the MPs) the dowels shouldnt be anywhere near bottoming out in the head. Have you tapped out every head bolt hole with a bottoming tap? (not one that's tapered..the bottoming ones are almost flat like an end mill) Do you use a torque wrech, and tighten in the proper steps and sequence? You should be going in 3 steps. IIRC, the final spec is 85 pound feet. So, tap the holes and blow them out with compressed air. Wire wheel the bolts themselves to get any crud out of the threads. Use 30W oil (not 10-40, 10-30 would be ok) on the threads, and only a little, dont get it all over the place. No finger prints or grease allowed on the head or block gasket surfaces. Clean it with a clean paper towel or lint free rag, then dont touch either surface with your hands. Put the head in place, start with the center bolts (I start all the bolts by hand as far as I can go) and torque them all to 40 pound feet. Then go back, torque them all to 65. Then finally go back and get them all to 85 in a smooth motion. I've done over 50 engiens this way, and never had a leak or blown gasket due to "normal" use. (NOS will kill the small block ones tho..

I used new Arp bolts this time and last time factory. I did all of the above, I have built several engines but have never had this problem be so common....

[Follicly Challenged]

Something drastically wrong. Never lost a head gasket on a BB Mopar, EVER ! Same spot both times ? and you swapped blocks ? Must be the head !

[Morris'_Mopars]

Something drastically wrong. Never lost a head gasket on a BB Mopar, EVER ! Same spot both times ? and you swapped blocks ? Must be the head !

I had the heads checked also. Had them resurfaced to make sure they are flat.
I am using the fel-pro gaskets which I have used for years. Wonder if it might be the gaskets???

[moper]

You're missing something. My vote is for the dowel bottoming out in the head for some reason. You can usually remone them with vice grips, just dont mangle them too badly. You only need a short stub to align the head and gasket. I'd pull them both on that side and remove like .020 off them. It's possible the block you used was milled at some point in its life, and now the dowel is sticking out too far into the head. That's my guess anyway.

[Follicly Challenged]

Bump the above, you check the dowel ?

[Morris'_Mopars]

Bump the above, you check the dowel ?

Yep, and it appears to be ok

[Follicly Challenged]

I dunno, I'm stumped !

If you've got a flat block surface, and, a flat head surface, with a gasket in between, and, they're clamped together with bolts at correct preload, with nothing to impair that clampload(dowel sticking up),

IT SHOULD SEAL !

[tactransman]